Feeding habits of two congener species of seabreams, Pagellus bogaraveo and Pagellus acarne, off the Azores (northeastern Atlantic) during spring of 1996 and 1997

The blackspot seabream, Pagellus bogaraveo, has traditionally been the main target species of the bottom longline fishery in the Azores. However, in recent years several other species have increased in economic importance, including the axillary seabream, Pagellus acarne. Despite their commercial value, few studies regarding their diet composition were found in the literature. Data were collected during the demersal cruise surveys that took place aboard the RV Arquipélago during the spring of 1996 and 1997. The stomach contents of blackspot and axillary seabreams were examined to define their diets. Both seabreams studied fed on a wide variety of small organisms, mainly fishes and several invertebrates. Prey fishes were important in the diets of both blackspot seabream and axillary seabream (61.3 and 76.3% frequency of occurrence, respectively). Thaliaceans and ophiuroids were the most important invertebrates for both species. In addition, blackspot seabream also fed upon pelagic gastropods while axillary seabream consumed bivalves and echinoids. Prey composition of the blackspot seabream diet varied mainly due to the use of different environments, and consequently prey availability. The feeding behavior of this species appears to be size related, as small individuals are mostly males and live preferentially in coastal areas and shallower waters, and exhibit different feeding habits from those observed for larger individuals, which are mainly females and live preferentially at offshore banks and deeper waters. Prey composition indicated that both predators have the ability to feed near the bottom on benthic prey as well as pelagic species in the water column. This study suggests that in addition to locally produced food, the productivity of many seamounts communities is also dependent on a regular supply of productivity that drift past seamount. Although the results of the stomach contents analysis showed a significant feeding overlap, we suggest that they may not be sharing resources with each other, because the trophic activities of the two species are segregated by differences in habitat use. In this study, habitat partitioning appeared to be an important factor in preventing diet overlap.